1. Field of the Invention
The present invention relates generally to a data communication method and apparatus in a mobile communication system. In particular, the present invention relates to a method for providing a push service to a mobile terminal and a push server apparatus using the same in a mobile communication system for high-speed data transmission in order to facilitate a data receiving service such as transmission of paging messages for the mobile terminal.
2. Description of the Related Art
Mobile communication systems typically use three principal multiple access schemes. These are Frequency Division Multiple Access (FDMA), Time Division Multiple Access (TDMA), and Code Division Multiple Access (CDMA). In FDMA, the bandwidth of the available spectrum is divided into separate channels, each channel being allocated to a subscriber. In TDMA, the same spectrum channel frequency is shared among a plurality of subscribers by dividing it over time. In CDMA, a plurality of subscribers occupy the same frequency at the same time and they are separated from each other by different codes allocated to them. Along with the rapid development of communication technology, these mobile communication systems now provide mobile terminals with high-speed data service enabling transmission of a larger volume of digital data, such as moving pictures as well as e-mails and still images, in addition to the typical voice call service.
Mobile communication systems supporting the high-speed data service include CDMA2000 1× now in service, Evolution Data Only (1×EV-DO) enabling high-speed data transmission, and International Mobile Telecommunication 2000 (IMT-2000), which is a future-generation mobile communication system under study for transmission/reception of voice and packet data irrespective of place and time. The CDMA 2000 1× system provides data service at a forward data rate of 144 kbps over the IS-95C network, which has evolved from the IS-95A/ISD-95B network, that is faster than in IS-95A/ISD-95B networks that offer 14.4 kbps/56 kbps. The 1×EV-DO standard is one of the standards proposed, by service providers such as Qualcomm, for transmission of a larger volume of digital data. The 1×EV-DO standard has evolved from CDMA2000 1× to be able to provide a forward data rate of about 2.4 Mbps. The 1×EV-DO network provides data service with a Point-to-Point Protocol (PPP) session established for a mobile terminal, as specified in the standard.
Depending on the connection state of the PPP session, the mobile terminal is placed in an active state, a dormant state, and an idle/null state in the 1×EV-DO network. In the active state, the mobile terminal transmits/receives data to/from a correspondent node (CN) such as an external host connected to an Internet Protocol (IP) network like the Internet via a packet data service node (PDSN) as defined in the CDMA2000 1× network.
In the dormant state, although the PPP session is still connected, a radio bearer for wireless data transmission is released due to the absence of data transmission/reception for a predetermined time period. Yet, the mobile terminal can resume data transmission/reception with the CN. However, in the idle/null state, the PPP session has not been established or is terminated between the mobile terminal and the packet data service node (PDSN). Without a PPP reconnection, the mobile terminal cannot transmit/receive data to/from the CN.
In the idle/null state, therefore, a paging message or a packet cannot be delivered from the CN to the mobile terminal by a data receiving service over the conventional 1×EV-DO network. Especially, considering that an additional service, such as a video call service, is expected to be provided to the mobile terminal, the data receiving service is essential.
To provide the data receiving service with the conventional 1×EV-DO network configuration, IP addresses must be allocated to all mobile terminals and they must be connected to the network. However, this method is not viable in the present Internet Protocol version 4 (IPv4) address system. Accordingly, there exists a need for notifying a mobile terminal in an idle/null state of incoming data, such as a paging message.